Gene that dramatically increases colorectal cancer risk uncovered

Published: Friday, August 15, 2008, 13:03 [IST]

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Washington, August 15 : Northwestern University scientists in the U.S. claim to have discovered a major genetic trait which is present in 10 to 20 per cent of colorectal cancer patients, and appears to be the most common cause of the disease.

The researchers say that the trait, dubbed TGFBR1 ASE, increases an individual's lifetime risk of developing colorectal cancer is 50 per cent, compared to six per cent for the general population.

"This probably accounts for more colorectal cancers than all other gene mutations discovered thus far," said Dr. Boris Pasche, director of the Cancer Genetics Program at the university's Feinberg School of Medicine.

"The reasonable expectation is this finding will save some lives. We will be able to identify a larger number of individuals that are at risk of colorectal cancer and, in the long term, maybe decrease the cases of colorectal cancer and of people dying from it by being able to screen them more frequently," added Pasche, who is a lead author of the paper published in the online edition of the journal Science.

The researchers say that the trait results in decreased production of a key receptor for TGF-beta, the most potent inhibitor of cell growth.

With less of this vital protective substance to inhibit cell growth, colon cancer can more easily develop.

This is the first time that a study has shown that decreased production of this receptor for TGF-beta was present in 10 to 20 per cent of colorectal cancer patients.

Decreased production of the same receptor was present in only one to three per cent in healthy control groups.

Pasche said revealed that the findings were based on a Caucasian population, and insisted that they needed to be confirmed in other studies.

The researcher expects that a clinical test will soon be developed that could be offered to families with a history of colorectal cancer, and other individuals to determine whether they carry this mutation.